Electric space heater



AU8 4 1970 c. R. KENNEDY 3,523,180

ELECTRIC SPACE HEATER Filed Feb. l, 1967 United States Patent Office 3,523,180 Patented Aug. 4, 1970 3,523,180 ELECTRIC SPACE HEATER Chester R. Kennedy, 47 Highland St., Brockton, Mass. 02401 Filed Feb. 1, 1967, Ser. No. 613,286 Int. Cl. F24h 7/04; H05b J/00 U.S. Cl. 219-367 7 Claims ABSTRACT F THE DISCLOSURE A space heater comprising a bank of radiator tubes connected at alternate ends to form a circuitous path for flow of fluid through the tubes, a fluid heater connected to the lowermost of the radiator tubes for supplying heated fluid thereto, and a return loop connected to the uppermost radiator tube and to the fluid heater for returning the cooled fluid at the top of the bank of tubes to the heater for reheating and continued circulation.

BACKGROUND OF THE INVENTION Space heaters of the foregoing kind are disclosed in such patents as Alexander, 2,736,790 and 2,841,685; Uhlig, 3,179,788; Brand, 2,894,108; Reynolds, 2,772,342 and Eggleston, 1,941,855. However each of these patents fails to disclose a structure which makes efficient use of the electrical input so that the operating cost is too high in proportion to oil and gas heated units to be acceptable.

SUMMARY The disadvantages inherent in the heating units referred to above are overcome herein by the heat-radiating unit which forms the subject matter of this invention and which comprises a plurality of vertically spaced, oppositely inclined radiator tubes, each of which has on it radiating fins. The upper end of an oppositely inclined fluid heating tube situated below the lowermost radiator tube is connected to the lower end of the lowermost radiator tube and contains a heating element mounted at its lower end and extending axially along the tube toward its higher end. A return tube comprising a loop which extends from the upper end of the uppermost radiator tube to the lower end of the fiuid heating tube provides for continuous circulation of the heated uid upwardly to the tubes from the heating tube to the top and from thence downwardly through the return tube to the heating tube for reheating. The adjacent ends of the fluid heating tube and radiator tube above it and successive radiator tubes are connected by fittings designed to receive the ends of the tubes therein with interior surfaces of the fittings and tubes flush. An expansion tube is connected to the lower end of the uppermost radiator tube, there is an aquastat connected to the expansion tube and there is means operable by the aquastat to activate and de-a'ctivate the heating element. The unit is contained in a housing which supports it with the radiator tubes parallel to the wall of the room in which it is situated and the housing has an opening adjacent the floor below the unit. A duct extends from the housing toward the top of the room and there is a blower fan mounted in the duct operable to induce air at the top of the room,

drive it downwardly through the radiator unit and through the opening at the bottom into the room at floor level. The housing contains a front opening adjacent the top of the bank of radiator tubes, there is a valve plate movable from a position covering this opening to a position covering the lower end of the duct, and means for effecting movement of the valve plate to cover the front opening when the blower is in operation and to cover the lower end of the duct when the blower is inoperative. A filter is preferably mounted in the duct between the blower and the top of the housing.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

FIG. l is a front view of the heating unit with the front wall of the housing broken away to show the radiator tubes;

FIG. 2 is a section taken on the line 2-2 of FIG. l; and

FIG. 3 is a fragmentary section through the junction between a radiator tube and the fitting by means of which it is connected to the adjacent end of the next radiator tube.

As herein illustrated, the heating means comprises a bank of vertically spaced tubes, a lower tube 10 which is a fluid heating tube, an upper tube 12 which is an expansion tube, and intermediate tubes 14 whichk are yradiator tubes. Each radiator tube has on it radiating fins 16. The heating tube 10 is inclined upwardly relative to the horizontal at an angle of about 2 to the horizontal and the successive radiator tubes 14 are inclined upwardly at corresponding angles in opposite directions, the uppermost radiator tube 14 being substantially parallel to the heating tube 10. The adjacent ends of the radiator tubes are connected to each other and the lowermost radiator tube to the heating tube by fittings 18. It is irnportant to employ fitttings with inside diameters corresponding to the inside diameters of the tubes and to join them without interrupting the continuity of the inside surfaces from one tube to the next thereby to substantially eliminate frictional resistance to flow of the fluid medium within the tubes. Such a fitting is illustrated in FIG. 3 wherein the end of the tube 14 is soldered into an enlargement at the end of the fitting 18 with the end of the tube seated against the shoulder at the bottom of the enlargement and by confining the solder to the surfaces between the inner side of the enlargement and the outer side of the portion of the radiator tube inserted into the enlargement. The fitting 18 may be a casting with the enlargements at the ends machined to receive the ends of the radiator tubes, or it may be a thin wall tube shaped and drawn to provide enlargements at the ends for receiving the ends of the radiator tubes. The tubings and fittings are preferably copper or copper alloy.

The fins are aluminum and are commercially available for application to the size tube with which they are to be employed.

The lower end of the heating tube 10 is soldered into one end of a fitting 20. The opposite end of the fitting 20 is threaded interiorly and an adapter 22 mounting a heating element 24 in the form of a slender loop is screwed into the fitting to hold the loop within the tube. A head 26 on the adapter provides for easily removing or replacing the heating element and a conductor 28 provides for supplying current shown) within the heatingelement.

Fluid heated within the heating tube ascends through the radiator tubes to the top of the unit and is returned to the bottom of the unit for reheating by way of a return loop 30 so as to maintain a continuous circulation of fluid through the unit. The return loop 30 has an upwardly inclined lower portion 32 below and nearly parallel to the heating tube and a vertical portion 34 extending upwardly from the portion 32 to the level of the uppermost radiator tube 14. The iitting has at its lower sidel a lateral 20a into which the lower end ofthe portion 32 is soldered andelbow fittings 36 connect the upper end of the portion 32 tothe lower en-d of the portion 34 and the upper end of the portion 30 t0 the upper end of the uppermost radiator tube. The elbow ttings 36 are designed like the fittings 18 to provide uniformly smooth interior vsurfaces at the junctions substantially free of friction.

The iitting to which the lower end of the uppermost radiator tube 14 is connected has an upwardly extending lateral 18b containing a side opening into which one end of the expansion tube 12 is soldered and a top opening into which is threaded an adapter 38 mounting an aquastat 40. The aquastat 40 operates through suitable connections to control activation of the heating element 24.

The entire unit is mounted in a sheet metal housing 46 of such dimensions as to tit between the wall studdng of the room in which the unit is to be employed. The housing 46 is substantially rectangular in horizontal crosssection, having back and front walls 48 and 50, and provides a vertical closed chamber for the unit. Optionally, the back wall could be omitted and a reilective sheet material such as aluminum foil placed against the wall behind the unit. At the bottom of the chamber in the front wall there is an opening 52 just below the return tube portion 32 at iloor level. The lower end of a duct 54 is connected to the top of the housing substantially midway between the opposite sides and extends therefrom up to the ceiling where it is connected to the discharge side of an induction fan 56, operation of which induces the air at the top of the room into the duct 54, forcing it downwardly therethrough and through the housing 46 over the heating unit and through the bottom opening 52 into the room at floor level. A conventional wall thermostat T provides for starting and stopping the induction fan. A second opening 58 is provided in the front wall 50 adjacent the upper end of the housing at about its junction with the duct 54 and a valve plate 60 is pivotally connected at 62 to swing from a position covering the lower end of the duct 54 to a position covering the front opening 58. The valve plate 60 is designed to close the opening 58 when the fan is in operation so that the induced air from the top of the room is forced directly downward through the housing and bottom opening and when the fan is aaa-2,180Y

t0 a fesisfanealement (119?.

stopped in response to the thermostat T to close the lower p end of the duct 54 thereby permitting the heat rising from the heating unit to ow upwardly through the opening 58 into the room. The valve plate may be actuated by a solenoid or small reversible motor which in turn is activated at the right time to position the valve plate in an open or closed position with respect to the lower end of the duct 54 by the thermostat T which controls the fan.

The duct 54 is provided with an opening through one side for removably receiving a lter element 64.

The unit as described above responds very rapidly to its control and so affords very uniform heating and has proved to be extremely economical in operation.

The inclination of 2 described herein for promoting natural ilow and pumping action during heating has proved very effective; however it is within the scope of the invention to vary the angle between about 1 and 5 depending upon the size and nature of the installation,

As is customary, an antifreeze is mixed with the uid medium to prevent freezing in the event the unit should 4 become Ainoperative through failure of some kind during cold Weather. i Y

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents falling within the scope of the appended claims.

I claim:

1. A heat radiating unit comprised of a bank of vertically spaced radiator tubes, adjacent tubes of which diverge, and wherein the lowermost tube inclines downwardly relative to the horizontal at least approximately 2 and the uppermost tube inclines upwardly relative to the horizontal at least approximately 2, radiating tins on each tube, a iluid heating tube at the lower end of the bank of tubes, said tiuid heating tube being inclined upwardly relative to the horizontal at least approximately 2 and being connected at its upper end to the lower end of the lowermost radiator tube, said iiuid heating tube being devoid of radiator fins, a heating element situated in the lower end of the fluid heating tube, said heating element projecting axially along said fluid heating tube toward its higher end, and a return tube connected at its upper end to the upper end of the uppermost radiator tube and at its lower end to the fluid heating tube adjacent its lower end.

2. A heat-radiating unit according to claim 1, wherein there are fittings at the adjacent ends of successive radiator tubes designed to` receive the ends of the radiator tubes therein with the interior surfaces of the fittings and radiator tubes flush.

3. A heat-radiating unit according to claim 1, wherein said heating element comprises a long slender loop supported within the heating tube substantially at its longitudinal axis.

4. A heat-radiating unit according to claim 1, wherein the return loop comprises tube portions extending laterally from the lower end of the heating tube and substantially vertically to the upper end of the uppermost radiator tube.

5. A heat-radiating unit according to claim 1, comprising an expansion tube connected to the uppermost radiator tube. Q 6. A heat-radiating unit according to claim 5, comprising an aquastat connected to the uppermost radiator tube adjacent the expansion tube, and means operable by the aquastat to activate and de-activate 'the heating unit.

7. A heat-radiating unit comprising a bank of vertically spaced radiator tubes, each of which is inclined at approximately not less than 2 to the horizontal and adjacent ones of which diverge with respect to each other, fitting at the adjacent ends of successive radiator tubes receiving said ends with the interior surfaces of the fittings and radiator tubes flush, tins on each of the said radiator tubes, a fluid heating tube at the lower end of the bank of tubes, said fluid heating tube being inclined upwardly relative to the horizontal not less than 2 and being connected at its upper end to the lower end of the lowermost radiator tube, said fluid heating tube being devoid of fins, a heating element comprising a long slender loop supported withinsaid fluid heating tube, said heating element being situated at thelower end ofthe fluid heating tube and projecting axially along said fluid heating tube toward its higher end, a return tube connected at its upper end to the upper end of the uppermost radiator tube and at its lower end to the lower end of the uid heating tube adjacent its lower end, and an expansion tube connected to the uppermost radiator tube, said heat-radiating unit also comprising a housing Within which it is supported, said housing being adapted to support the radiator tubes parallel to the wall of the room in which the unit is situated and having a front opening adjacent the bottom near iloor level below the lowermost radiator tube and a front opening at the topabove the uppermost radiator tube, a duct extending from the topto the upper region of the room being heated, a valve plate supported for movement from a position covering said top'opening to a position covering the duct, an induction fan in the duct operable to induce air into the upper end of the duct and force it downwardly over the heating unit and through the bottom opening at the floor level, means operable on the one hand to hold the plate over the top opening and on the other hand to hold the plate over the duct when the fan is stopped, and a thermostat for effecting operation of the induction fan and said last named means. t

References Cited UNITED STATES PATENTS 5/1918 Savage 219--341 9/1933 Slagel 165-178X 5 1956 McElhaney 219-341 10/ 1958 Alexander 219-365 10/1966 Brusven 219-365 12/ 1887 Walker 237--17 12/1934 Carr 219-341 FOREIGN PATENTS 10/ 1964 Germany.

5/ 1960 France.

9/ 1940 Norway.

ANTHONY BARTIS, Primary Examiner U.S. Cl. X.R.

2,337,518 12/1943 Young etal. 165-122X 15 219-341, 365, 370; 237-16; 165-106; 126-101 

